<template>
  <div ref="dragDiv" class="drag">
    <div class="drag_bg"></div>
    <div class="drag_text">{{ successStatus ? successTips : tips }}</div>
    <div ref="moveDiv" class="handler handler_bg" :class="{ handler_ok_bg: successStatus }" @touchstart="slideStart" @mousedown="slideStart"></div>
  </div>
</template>

<script>
export default {
  name: 'VerifySlider',
  props: {
    tips: {
      type: String,
      default: '请按住滑块，拖动到最后边'
    },
    successTips: {
      type: String,
      default: '验证通过'
    }
  },
  data() {
    return {
      config: {
        clientType: null,
        startEvent: null,
        moveEvent: null,
        endEvent: null,
        getClientX: null
      },
      successStatus: false,
      beginClientX: 0 /* 距离屏幕左端距离 */,
      mouseMoveStatus: false /* 触发拖动状态  判断 */,
      maxWidth: '' /* 拖动最大宽度，依据滑块宽度算出来的 */
    }
  },
  created() {
    this.initConfig()
  },
  mounted() {
    this.maxWidth = this.$refs.dragDiv.clientWidth - this.$refs.moveDiv.clientWidth
    document.getElementsByTagName('html')[0].addEventListener(this.config.moveEvent, this.slideMove)
    document.getElementsByTagName('html')[0].addEventListener(this.config.endEvent, this.slideEnd)
  },
  methods: {
    slideStart(e) {
      if (this.successStatus) return
      e.preventDefault && e.preventDefault() // 阻止文字选中等 浏览器默认事件
      this.mouseMoveStatus = true
      this.beginClientX = this.config.getClientX(e)
    },
    slideMove(e) {
      if (!this.mouseMoveStatus) return
      const width = this.config.getClientX(e) - this.beginClientX
      if (width < 0) return
      if (width <= this.maxWidth) {
        this.$el.getElementsByClassName('handler')[0].style.left = width + 'px'
        this.$el.getElementsByClassName('drag_bg')[0].style.width = width + 'px'
      } else if (width > this.maxWidth) {
        this.successFunction()
      }
    },
    slideEnd(e) {
      this.mouseMoveStatus = false
      const width = this.config.getClientX(e) - this.beginClientX
      if (width < 0) return
      if (width < this.maxWidth) {
        this.$el.getElementsByClassName('handler')[0].style.left = 0 + 'px'
        this.$el.getElementsByClassName('drag_bg')[0].style.width = 0 + 'px'
      }
    },
    successFunction() {
      this.successStatus = true
      this.$emit('success', '成功') // 把状态传给父组件
      document.getElementsByTagName('html')[0].removeEventListener(this.config.moveEvent, this.slideMove)
      document.getElementsByTagName('html')[0].removeEventListener(this.config.endEvent, this.slideEnd)
      document.getElementsByClassName('drag_text')[0].style.color = '#606266'
      document.getElementsByClassName('handler')[0].style.left = this.maxWidth + 'px'
      document.getElementsByClassName('drag_bg')[0].style.width = this.maxWidth + 'px'
    },
    getClientX(e) {
      if (this.config.clientType === 'mobile') {
        return e.changedTouches[0].clientX
      } else {
        return e.clientX
      }
    },
    initConfig() {
      this.config.clientType = navigator.userAgent.match(/(iPhone|iPod|Android|ios)/i) ? 'mobile' : 'pc'
      if (this.config.clientType === 'mobile') {
        this.config.startEvent = 'touchstart'
        this.config.moveEvent = 'touchmove'
        this.config.endEvent = 'touchend'
        this.config.getClientX = e => e.changedTouches[0].clientX
      } else {
        this.config.startEvent = 'mousedown'
        this.config.moveEvent = 'mousemove'
        this.config.endEvent = 'mouseup'
        this.config.getClientX = e => e.clientX
      }
    }
  }
}
</script>

<style lang="scss" scoped>
* {
  box-sizing: border-box;
}
.drag {
  position: relative;
  background-color: rgb(250, 250, 250);
  width: 290px;
  height: 40px;
  line-height: 38px;
  text-align: center;
  border-radius: 4px;
}
.handler {
  position: absolute;
  top: 0;
  left: 0;
  width: 40px;
  height: 40px;
  border: 1px solid #dcdfe6;
  border-radius: 4px;
  cursor: move;
}
.handler_bg {
  background: #fff
    url('')
    no-repeat center;
}
.handler_ok_bg {
  background: #fff
    url('')
    no-repeat center;
}
.drag_bg {
  background-color: #e2f3d9;
  border: 1px solid #d4edc6;
  border-right: 0;
  height: 40px;
  width: 0;
}
.drag_text {
  border: 1px solid #dcdfe6;
  border-radius: 4px;
  position: absolute;
  top: 0;
  width: 100%;
  font-size: 14px;
  text-align: center;
  -moz-user-select: none;
  -webkit-user-select: none;
  user-select: none;
  -o-user-select: none;
  -ms-user-select: none;
}
</style>
